This invention relates to a wheel and final drive assembly having a ring gear output for ground-driven work machine, such as an off-highway truck.
Large earth working machines, such as large mining trucks, typically have at least one pair of driven wheels that are rotatably mounted on corresponding axles or spindles. Each wheel may be driven through a final drive assembly, which is typically a double reduction planetary gear arrangement. Typical planetary gear arrangements include a sun gear rotatably coupled to an input shaft, a set of planetary gears disposed about the sun gear and held by a carrier, and a ring gear disposed about the planetary set. The double reduction gear arrangements typically have an input to a first reduction sun gear and an output through a second reduction carrier or ring gear. Power transfer from the first reduction planetary set to the second reduction gear set can be through the first carrier to the second sun gear. A final drive adapter is used to transmit the final output to the rotatably mounted wheel. The final drive adapter couples the second reduction gear assembly to the wheel via a second carrier to wheel adapter or a second ring gear to wheel adapter.
As the size and capacity of large work machines increases, greater amounts of gear reduction are required to move the machines across the ground. Because the final drive must be confined within the wheel and rim, the structural design and geometric configuration of the final drive adapter can impact the amount of gear reduction. Another problem incurred when designing final drive assemblies with greater gear reduction is the ability to perform routine maintenance. It is preferable, although not always possible, to provide a wheel and final drive assembly that permits maintenance and service of the gear reduction portion of the final drive assembly without having to remove the outboard tire and rim.
In U.S. Pat. No. 6,148,941, a wheel and final drive assembly having a carrier output adapter is described. The output of the reduction gear assembly is maximized by providing a segmented rim mounting flange attached to an inboard surface of the wheel. The segmented rim mounting flange permits access to the mechanical components of the reduction gear assembly without the need to remove the outboard rim. Although this design increased the amount of gear reduction through the final drive, the continued increase in machine size creates a need for a further increase in gear reduction.
In one aspect of the present invention, a wheel and final drive assembly for a work machine is provided. The wheel includes an inboard rim mounting flange, an outboard mounting flange and an intermediate portion. The final drive assembly includes a first planetary gear reduction assembly and a second planetary gear reduction assembly. The second gear reduction assembly is positioned outboard of the first gear reduction assembly. A substantially cylindrical ring gear adapter includes an inboard end, and outboard end and an inner surface having a plurality of teeth disposed thereabout. The ring gear adapter interacts with the first and second reduction gear assemblies and is removably attached to the outboard end of the wheel.
In another aspect of the present invention, a work machine having a wheel and final drive assembly is provided. The wheel includes an inboard rim mounting flange, an outboard mounting flange and an intermediate portion. The final drive assembly includes a first planetary gear reduction assembly and a second planetary gear reduction assembly. The second gear reduction assembly is positioned outboard of the first gear reduction assembly. A substantially cylindrical ring gear adapter includes an inboard end, and outboard end and an inner surface having a plurality of teeth disposed thereabout. The ring gear adapter interacts with the first and second reduction gear assemblies and is removably attached to the outboard end of the wheel.